Question

Monochromatic light of wavelength $589nm$ is incident from air on a water surface. What are the wavelength and speed of refracted light? Refractive index of water is 1.33 .

• A. $4.20\times 10^{-8}$ and $4.0\times 10^{7}m/s$
• B. $3.68\times 10^{-9}m$ and $3.02\times 10^{7}m/s$
• C. $1.9\times 10^{-10}m$ and $3.2\times 10^{8}m/s$
• D. $4.42\times 10^{-7}m$ and $2.25\times 10^{R}m/s$

Answer 1

Answer: (D)

For refracted light (In this process wavelength and speed changes but frequency remains the same)
Wavelength of refracted light ${\lambda }^{\prime }=\frac{\lambda }{\mu }$
$=\frac{589\times 10^{-9}}{1.33}$
$=4.42\times 10^{-7}m$
Velocity of refracted light $v=\frac{c}{\mu }=\frac{3\times 10^8}{1.33}$
$=2.25\times 10^{8}m/s$